JPS5821032B2 - Hakumaku Denkai Houto Sonosouchi - Google Patents

Description

[Detailed description of the invention] The present invention relates to a thin film electrolysis method and an apparatus thereof.

Electrolytic reactions occur as a pair of anodic reactions and cathodic reactions, but in reality, only either anodic oxidation or cathodic reduction is often required.

At that time, the reaction at the opposite pole has the opposite effect, making the effect worse.

Conventionally, a diaphragm or the like has been used to prevent the products near each pole from mixing with each other, thereby reducing this obstruction.

Furthermore, when there is no electrochemically active substance in the sample with respect to the opposite electrode, for example, in the case of an aqueous solution, water electrolysis occurs.

In this case, since the overvoltage is high, the voltage required for electrolysis is usually high.

As a countermeasure against this, a depolarizer is used, and as a depolarizer oxygen (
or air) may be used.

In this case, these gases are usually blown into the electrolytic cell, but its effectiveness is limited by a significant increase in ohmic resistance due to bubbles, the rate of oxygen diffusion in the sample solution to the cathode surface, etc. It also has the disadvantage of being complicated.

In order to eliminate these drawbacks, the present inventors developed a thin film-forming body into one
By attaching it between two electrodes and forming a thin film of electrolyte, equilibrium between the electrolyte and the gas phase is quickly achieved, and the effects of removing reaction product gas and absorbing depolarizer gas are significantly increased. The present invention was achieved by discovering that.

The present invention is directed to a connected electrode body formed by vertically connecting two or more electrolytic units configured to keep the inter-electrode distance at 10 mm or more by installing a thin film forming body between the cathode and the cathode. A thin film electrolysis method characterized by supplying an electrolytic solution, allowing it to flow downward while forming a uniform and stable thin film on a connected electrode body, and bringing this liquid phase thin film into contact with a gas to perform electrolysis. It is.

Furthermore, the present invention is formed by connecting two or more electrolytic units vertically in an electrolytic cell, which are configured to keep the distance between the electrodes at 10 mm or more by installing a thin film forming body between the negative and positive electrodes. This is an electrolytic device used for thin film electrolysis, characterized in that a connected electrode body is provided, an electrolytic solution supply port is provided in the upper part of the electrolytic cell, and a gas inlet port is provided in the lower part.

Suitable materials for the electrode used in the present invention include platinum, gold, lead peroxide, graphite, titanium, palladium, iron, aluminum, stainless steel, lead, nickel, magnetite, etc., or composites thereof, and the shape thereof may be spherical or rod-like. , may be plate-like, thread-like, string-like, paper cloth-like, etc., and may be hollow, net-like,
It may be in the form of a fabric, a porous body, etc., and may be surface-treated (plating, coating, oxidation treatment, peroxidation treatment, etc.).

Examples of thin film forming materials include glass, porcelain, cellulose, plastic, carbon, and titanium oxide.

Stainless steel, asbestos, perlite, etc. are used alone or in combination, and paper, cloth, etc. are also used in some cases.

The shape, material, size, etc. of the thin film forming body are appropriately selected depending on the electrical conductivity and flow rate of the electrolytic solution.

The electrode and the thin film forming body are usually mounted in contact with each other, but they do not necessarily need to be in contact with each other.

In particular, when a conductive substance is used as a thin film forming body, it is necessary to provide a gap or insert a non-conductive substance in between to prevent direct contact with the electrode.

Maintaining a steady liquid film between the electrodes 2 depends on the interfacial tension between the electrode and the electrolyte gas phase, the type and viscosity of the electrolyte, the type, shape, and size of the electrode material, and the flowing velocity (linear velocity) of the electrolyte. Determined by etc.

For example, when the electrolyte is a dilute aqueous solution and is constantly flowed down as a thin film with a certain width, if the distance between the electrodes is 5 mm or more, it is not possible to constantly bridge the electrolyte with the dilute aqueous solution. (Thin film forming body) Without it, it is extremely difficult.

In the device of the present invention, the distance between the electrodes that is actually required is about 1
It is 0 mm or more.

The shape of the thin film forming body may be spherical, rod-like, plate-like, thread-like, string-like, paper cloth-like, etc., and may also be hollow, net-like, woven, porous, etc., and may be similar to electrodes. It may also be surface-treated.

One or more electrodes are used depending on the number of electrodes.

If a hollow, net-like, multi-porous material is used, a thin film effect can be obtained even on the inner surface of the thin film forming body.

The electrodes may be installed vertically, horizontally, or diagonally.

It is preferable that the electrolytic solution flows down as uniformly as possible from the supply port above the connecting electrode body using, for example, a shower.

In order to guide the electrolyte uniformly onto the connecting electrode body or to prevent it from scattering, non-conductive threads, nets, tapes, etc. may be provided along the connecting electrode body as necessary, or the electrodes and Alternatively, the electrolyte may be guided by providing uneven notches (grooves, etc.) on the thin film forming body.

As the gas to be brought into contact with the electrolytic solution, oxygen, air, chlorine, ozone, etc. are used in the case of an oxidation reaction, and hydrogen, etc. are used in the case of a reduction reaction.

Depending on the reaction conditions, an inert gas such as nitrogen is used, and if the reaction gas is to be easily separated and recovered, water vapor,
Carbon dioxide gas or the like may also be used.

To explain an embodiment of the present invention, for example, when electrolytic oxidation is performed, an electrolytic solution undergoes electrolytic oxidation at an anode.

In conventional methods, this oxidation product moves close to the cathode and undergoes some electrolytic reduction.

However, according to the method of the present invention, since the thin film forming body connects the electrodes, the electrolyte flows down onto the surfaces of the successive electrodes and the thin film forming body, forming a continuous thin film, and the surface area of the thin film forming body is significantly reduced. To increase.

Therefore, for example, when oxygen is used as the surrounding gas phase, a large amount of oxygen is quickly absorbed into the electrolyte.

Further, when the anode product is a gas, the gas is quickly released into the gas phase, and the equilibrium is disrupted, making it easier for the reaction to proceed.

This effect also occurs near the anode.

In this way, the electrolytic solution that has sufficiently absorbed oxygen and removed the anode-generated gas reaches the vicinity of the cathode and undergoes a reduction reaction.

In this case, conventional methods involve re-reduction of the reaction products, e.g.
1□→C1- reaction occurs or hydrogen, etc. is generated due to reduction of water, but in the method of the present invention, since the electrolyte has sufficiently absorbed oxygen, OH- ions are generated by reduction of oxygen. occurs, so when looking at the reaction system as a whole, the potential difference, that is, the electric power required for oxidation is small.

When the anode product is a gas, it is sufficiently removed by the time it reaches the cathode, so that almost no re-reduction of the oxidation product occurs.

When the thin film-forming body is non-conductive, the ohmic resistance between the two electrodes increases, but this disadvantage is more than compensated for by the ease of obtaining the desired product.

In a device in which the electrodes are arranged horizontally, similar results can be obtained even if the positive and negative polarities are reversed.

In this case, when the reducing gas such as hydrogen gas generated at the cathode passes through both sides of the thin film forming body, it is quickly replaced with nitrogen in the gas phase and almost never reaches the anode, compared to the conventional method. This increases the oxidation efficiency of the electrolyte at the anode.

In the case of electrolytic reduction, for example the reduction of copper ions,
A similar effect can be obtained by using hydrogen gas in the gas phase.

On the other hand, when the electrolyte is a gas, if this gas is used alone or in a mixture with other gases, the gaseous electrolyte is quickly absorbed into the thin liquid phase, and the electrode surface is immediately absorbed. to receive electrolysis.

A remarkable electrolytic effect can be obtained not only when the gaseous electrolyte has good solubility in the electrolytic solution, but also when it has poor solubility.

The power source is usually direct current, but alternating current and pulsed waves can be used.

When a photochemical reaction or heating is required, electrolysis can be carried out while irradiating the liquid phase thin film with ultraviolet rays, infrared rays, or radiation from the side surface of the connecting electrode body.

For this purpose, it is preferable to provide a device for irradiating ultraviolet rays, infrared rays, or radiation for thin film liquid phase irradiation on the side surface of the electrolytic cell.

In conventional methods, it is extremely difficult to use photochemical reactions in combination with electrolytic reactions, but in the present invention, the irradiation can be easily applied directly to the electrode surface through the thin film, which has a remarkable effect on promoting photochemical reactions. synergistic effects can be expected when used in combination.

The apparatus used to carry out the method of the present invention will be described below.

FIG. 1 is a cross-sectional view showing an example of the electrolysis/seed molding device used in the present invention, and FIG. 2 is a vertical cross-sectional view taken along plane A-B in FIG. 1.
FIG. 3 is an enlarged view of a part of the connecting electrode body (the anode 1, cathode 2, and thin film forming body 3) in FIG. 2.

The electrolytic solution is introduced from the electrolytic solution supply pipe 8, dispersed by the small holes Jll, flows down to the electrode surface via the surface of the glass rod 16 to make the flow uniform, and forms a thin film 4, and then the anode 1.
(or cathode) and cathode 2 (or anode) to form a thin film 3
Electrolysis is performed across the

Further, as the electrolyte flows down onto subsequent electrodes, the electrolytic reaction is repeated continuously.

At the same time, a gas suitable for the electrolytic reaction is introduced through the gas introduction pipe 9, uniformly diffused into the electrolytic cell space 6 through the small hole 12, and exhausted to the outside through the gas exhaust pipe 10 through the small hole 13.

The liquid after electrolysis is taken out from the outlet 14.

During this time, for example, ultraviolet light can be irradiated by the irradiation device 7.

Although the electrolytic cell 5 is normally sealed, the electrolytic reaction can also be carried out in the atmosphere without sealing the outer frame 15.

This device can be connected in series, parallel, or a combination thereof depending on the capacity of the processing liquid.

The electric circuit can be connected not only in parallel but also in series or a combination of both, and the electrodes can also be used as bipolar electrodes.

FIG. 4 shows an example of parallel, FIG. 5 shows an example of series, and FIG. 6 shows an example of bipolar.

Note that it is also possible to perform thin film electrolysis by installing the connected electrode body in the atmosphere without an electrolytic bath and letting the electrolytic solution flow down from above and bring it into contact with the air.

In this device, since the liquid phase passes through the surface of the connecting electrode body in the form of a thin film, heating or cooling from the outside of the connecting electrode body, such as heating or cooling by infrared rays, hot air, cold air, etc., can be efficiently performed.

Furthermore, by using a hollow material as a connecting electrode body and heating or cooling the connecting electrode body itself by passing a heating or cooling medium through the hollow material, temperature control of various reactions according to the present invention can be performed quickly and efficiently. can be done.

The present invention is generally applicable to various reactions to which conventional electrolytic methods are applied.

Examples of such reactions include the following.

(1) Separation of electrolysable metal ions by oxidation or reduction, such as metals (Cu, Cd, Cr) in wastewater.

Co y Hg y Zn y Mn etc.) removal.

(2) Metals (Cu, Cd, Cr, Co, Hg, Zn, M
electrolytic scouring or electrolytic extraction of n, etc.).

(3) Organic wastewater treatment, for example, treatment of wastewater from dyeing industry, wastewater from food industry, etc.

(4) Deodorization treatment, for example, removal of hydrogen sulfide, mercaptan, sulfur dioxide gas, etc.

(5) Desulfurization and denitrification from flue gas.

(6) Destruction and agglomeration of colloids, such as destruction of O/W or W2O emulsions, agglomeration and removal of colloidal dispersed particles.

(7) direct or indirect electrolytic oxidation or reduction reactions of industrially available inorganic or organic compounds, such as hypochlorite, chlorate, perchlorate, caustic soda, by electrolysis of saline water; Production of chlorine, etc., production of permanganate from manganate, production of gluconate from glucose, production of succinic acid from maleic acid, production of hydroxylamine from nitric acid, etc.

Example 1 In the apparatus shown in Fig. 1, 100 graphite rods (electrodes) with an effective length of 1010 x 270 mm in diameter and 102 glass rods (thin film forming body) with an effective length of 10 x 270 mm were used.
An approximately 10-2 molar salt aqueous solution of copper sulfate containing 0p- was made to flow uniformly through the device at a rate of 60 rLl/min as an electrolyte, and a DC voltage of 40 V was applied between the electrodes.
Electrolysis was carried out by sufficiently absorbing hydrogen through the thin film in a hydrogen gas flow at a flow rate of 1/2.

When the electrolyzed solution was measured by atomic absorption spectrometry, it contained 1.5 iron as copper.

The copper ion removal rate was 98.5%.

Note that the current at this time was 250 to 450 mA.

Example 2 A stainless steel frame was used as the electrode instead of the graphite rod of the anode, and a vinyl chloride pipe wrapped in cotton cloth (broadcloth) was used instead of the glass rod as the thin film forming body, but otherwise the same as in Example 1. Electrolytic treatment was carried out in a hydrogen stream with an applied voltage of 40V.

The electrolyzed solution contained 1.4 p- of copper.

The copper ion removal rate was 98.6%. Example 3 A device similar to Example 1 was used, except that the electrical circuits were not connected in parallel, but instead a voltage of 40 mL was applied from both the upper and lower ends as shown in FIG.
Applying 00V and using other electrodes as bipolar, Example 1
In the same manner as above, a 10-2 molar salt aqueous solution of sodium cyanide containing 10p4 of CN- was prepared at 601 nJ! Electrolysis was carried out by flowing down at a rate of 1/min to sufficiently absorb oxygen in the air through the thin film in an air stream.

When the electrolyzed solution was analyzed by the method of JIS-KO102-29, the CN content was Q and 511P.

Also 20Hz AC and pulse electricity. Almost the same results as in the case of a DC power source were obtained when the source was changed to a DC power source and the other conditions were the same.

Example 4 Using the same equipment as in Example 1, a2sO to 10-2 mol.

60 ml of aqueous solution was allowed to flow down in 7 minutes, and a mixed gas of 1=1 of sulfur dioxide gas and oxygen was added at 600 TLl/min or 601 T.
applied at a rate of Ll/min with a current density of approximately 1 mA/CII
Electrolysis was performed by applying a DC voltage so that the voltage was I''.

Sulfur dioxide gas and oxygen were absorbed into the electrolytic solution through the thin film and underwent electrolytic oxidation, and the electrolyzed solution showed strong acidity and the production of sulfuric acid was observed.

When this is titrated with an aqueous potassium hydroxide solution and expressed as a sulfur dioxide gas removal rate in terms of sulfur dioxide gas, the mixed gas flow rate is 60
In the case of 0m11 minutes, it was 38%, and in the case of 60Trll/min, it was 75.

Note that the voltage change at this time was 32 to IV.

Example 5 The outer frame of the same electrolytic device as in Example 1 was removed, left open, and 102 methylene blue of 100 ppI11 was added.
M saline solution is allowed to flow down as an electrolyte at 60 ml/min,
A DC voltage of 50 V was applied between the electrodes.

Oxygen in the air was absorbed through the thin film, exhibiting a depolarizing effect.

When the methylene blue aqueous solution subjected to electrolytic oxidation was colorimetrically analyzed using a Hitachi spectrophotometer model 139, it showed a decolorization rate of 73.

The current value at this time was 350 to 500 mA.

Example 6 In Example 5, the electrolytic solution was irradiated with ultraviolet rays from a mercury lamp, and electrolysis was performed in the same manner as in Example 5. The methylene blue electrolyzed solution showed a decolorization rate of 93%,
Improved bleaching effect.

When the flow rate of the electrolyte was increased to 100 ml/min, radiation (cobalt 60) was used instead of the mercury lamp, and electrolysis was carried out in the same manner, a decolorization rate of 92 was obtained, and the flow rate was increased to 100 TL/min. However, the same level of decolorization effect was obtained.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an example of the electrolysis device of the present invention, and FIG.
The figure is a vertical cross-sectional view taken along the A-B plane of Fig. 1, and Fig. 3 is a longitudinal sectional view of the
An enlarged view of a part of the connected electrode body in the figure, Figure 4 is an example of connection when the electrodes are connected in parallel, Figure 5 is the connection when the electrodes are connected in series, and Figure 6 is when the electrodes are multipolar. 1 is a process diagram showing an example of the connection, in which symbol 1 is an anode, 2 is a cathode, 3 is a thin film forming body, 4 is a thin film of electrolyte, 7 is an irradiation device, 8 is an electrolyte supply pipe, 9 indicates a gas introduction pipe.

Claims (1)

[Scope of Claims] 1. A connected electrode body formed by vertically connecting two or more electrolytic units configured to keep the distance between the electrodes at 10 mm or more by installing a thin film forming body between the negative and positive electrodes. The electrolytic solution is supplied from the upper part of the connecting electrode body, and is allowed to flow downward while forming a uniform and stable thin film of the electrolytic solution on the connected electrode body, and this liquid phase thin film is brought into contact with gas to perform electrolysis. Thin film electrolysis method. 2. A connected electrode body consisting of two or more electrolytic units connected vertically in an electrolytic cell configured to keep the distance between the electrodes at 10 mm or more by installing a thin film forming body between the negative and positive electrodes. An electrolytic solution supply port is provided at the top of the electrolytic cell, and a gas inlet port is provided at the bottom of the electrolytic cell.
Electrolyzer used for thin film electrolysis.